Unique properties of graphene-based topological systems [1]}, [2]}, in conjunction with strong nonlinear optical interactions occurring in graphene, can be used to develop nonlinear photonic devices and systems, which can be used to optically control topologically-protected defect-immune light flow at the nanoscale. Key factors, such as large, tunable carrier densities [3]} and long intrinsic relaxation times up to the picosecond range [4]}, make graphene an ideal platform for topological plasmonics at high frequency, low loss, and large topological bandgaps. In particular, due to large optical near-field enhancement and extended life-time of plasmons in graphene metasurfaces, SHG, THG, FWM, and other nonlinear optical processes of plasmonic edge states can be achieved in graphene metasurfaces at ultralow optical power [5]}.
